The victim of sexually violent threats from an online stalker, singer Billy Joel's daughter refused to leave her New York City apartment for months last year until private investigators were able to help track down the digital predator, who turned out to a woman using a public library computer in Minnesota.

Before the woman could be tracked down in January, Billy Joel reached out to Beatles legend Paul McCartney for advice on protecting his daughter, Alexa Ray Joel, 27. Her mother, model and actress Christie Brinkley, was reportedly severely shaken by the experience, according to the New York Post.

Over the course of several months, 40-year-old Sheryl Finley reportedly sent Alexa Ray Joel more than 60 messages on Facebook dealing with "pedophilia, sadistic-sexual behavior, violent physical assaults and murder," according to court records obtained by the New York Post. The messages were written under the alias of Rick Steenfield.

Finley is from Austin, Minn., and the messages were traced back to computers at the Austin Public Library and Riverland Community College, reported ABC News local affiliate KAAL.

Investigators eventually found Finley naked in a wooded area of Austin. She told authorities she didn't intend to carry out the threats against Alexa Ray Joel "during this life," reported Britain's the Telegraph.

"Our client, a resident of New York, had been subject to months of sustained social media correspondence of a disturbing and sexually violent nature," the firm said on its website. "Working with local and state law enforcement, our analysts tracked, monitored and consolidated the aliases to identify the source of the attack. The alleged attacker, Sheryl Finley, is now awaiting trial."

Finley was charged with a felony count of stalking for electronic messages sent by false impersonation and misdemeanor stalking for repeated messages, according to the Austin Daily Herald, and was released from jail after posting bond. She has a pretrial date of May 3.

If convicted, Finley faces up to five years in prison and a fine of up to $10,000.

Alexa Ray Joel, a singer-songwriter who has performed with her father in the past, made headlines in 2009 for overdosing on pills during a bout with depression. She disputed the suggestion that she was attempting to commit suicide, telling ABC News, "I wasn't trying to kill myself . . . I was not suicidal."

The victim of sexually violent threats from an online stalker, singer Billy Joel's daughter refused to leave her New York City apartment for months last year until private investigators tracked down the digital predator, who turned out to a woman using a public library computer in Minnesota.